Display device, illumination device, and light guiding member

ABSTRACT

Display device is provided and includes display panel; and illumination device provided on rear surface side of display panel, wherein illumination device includes light sources, and light guiding member arranged at rear surface side of display panel, light guiding member has holes which penetrates the light guiding member, light sources are housed in corresponding hole, rear surface of light guiding member has first inclined surface inclined upwardly from light source housed in one of holes, front surface side of light guiding member has second inclined surface inclined upwardly from light source housed in one of the holes, and angle of first inclined surface to center line of one of holes is greater than angle of second inclined surface to center line.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.17/357,145, filed on Jun. 24, 2021, which application claims the benefitof priority from Japanese Patent Application No. 2018-245958 filed onDec. 27, 2018 and International Patent Application No. PCT/JP2019/039399filed on Oct. 4, 2019, the entire contents of which are incorporatedherein by reference.

BACKGROUND 1. Technical Field

What is disclosed herein relates to a display device, an illuminationdevice, a light guiding member, and a light guiding structure.

2. Description of the Related Art

As described in Japanese Patent Application Laid-open Publication No.2016-192263, configurations in which a plurality of point light sourcesare arranged with predetermined intervals to illuminate a display panelfrom the rear surface side have been known.

When the point light sources like light emitting diodes (LEDs) areemployed, luminance at positions directly above the LEDs is the highestand luminance at positions corresponding to intervals between the LEDsis relatively low.

For the foregoing reasons, there is a need for a display device, anillumination device, a light guiding member, and a light guidingstructure capable of reducing lowering of luminance due to a distancefrom a light source.

SUMMARY

According to an aspect, a display device includes: a display panelconfigured to transmit light; and an illumination device provided on arear surface side of the display panel. The illumination device includesa plurality of light sources configured to emit light, and a lightguiding member that has translucency and is arranged between the lightsources on the rear surface side of the display panel. The light guidingmember has a plurality of holes each of which opens in a first directionintersecting with a rear surface of the display panel and in each ofwhich a corresponding one of the light sources is disposed, and a lightguiding portion surrounding the holes. A rear surface of the lightguiding portion is provided with a first inclined surface inclined withrespect to the first direction and a plane orthogonal to the firstdirection.

According to an aspect, an illumination device provided on a rearsurface side of a liquid-crystal element, includes: a plurality of lightsources; and a light guiding member that has translucency and isarranged between the light sources. The light guiding member has aplurality of through-holes in each of which a corresponding one of thelight sources is disposed, and a light guiding portion surrounding thethrough-holes. A rear surface of the light guiding portion is providedwith a first inclined surface inclined so as to be closer to a frontsurface of the light guiding portion as a distance from the light sourceis increased.

According to an aspect, a light guiding member includes: a light guidingportion that has translucency and is provided with a through-holepenetrating the light guiding portion in a first direction so as tohouse a light source. A rear surface of the light guiding portion isprovided with a first inclined surface inclined so as to be closer to afront surface of the light guiding portion as a distance from thethrough-hole is increased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic multilayered structural view illustrating the mainconfiguration of a display device according to an embodiment;

FIG. 2 is a schematic perspective view illustrating the mainconfiguration of an illumination device when viewed from a surface side;

FIG. 3 is an X-Y plan view illustrating a relation between light sourcesand a light guiding member;

FIG. 4 is a cross-sectional view cut along line A-A in FIG. 3 ;

FIG. 5 is an enlarged cross-sectional view illustrating a configurationwithin a portion B in FIG. 4 ;

FIG. 6 is an enlarged cross-sectional view illustrating a characteristicconfiguration in a first modification;

FIG. 7 is an enlarged cross-sectional view illustrating a characteristicconfiguration in a second modification;

FIG. 8 is an enlarged cross-sectional view illustrating a characteristicconfiguration in a third modification;

FIG. 9 is an enlarged cross-sectional view illustrating a characteristicconfiguration in a fourth modification;

FIG. 10 is an X-Y plan view illustrating a relation between the lightsources and a light guiding member in the fourth modification;

FIG. 11 is an X-Y plan view illustrating a relation between the lightsources and a light guiding member in a fifth modification;

FIG. 12 is a diagram illustrating an example of the configuration onwhich mirror finishing has been performed;

FIG. 13 is a diagram illustrating an example of the configuration of alight guiding member in which second inclined surfaces are omitted;

FIG. 14 is a diagram illustrating an example of the configuration of alight guiding member in which second inclined surfaces are omitted; and

FIG. 15 is a view illustrating an example of the configuration of adisplay device that is different from the present disclosure.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be describedwith reference to the drawings. The present disclosure herein is merelyan example, and discretionary modifications within the gist of thedisclosure at which those skilled in the art can easily arrive arenaturally encompassed within the range of the present disclosure. In thedrawings, widths, thicknesses, shapes, and the like of the componentscan be schematically illustrated in comparison with actual modes formore clear explanation. They are merely examples, however, and do notlimit interpretation of the present disclosure. In the presentspecification and the drawings, the same reference numerals denotecomponents similar to those described before with reference to thedrawing that has been already referred, and detail explanation thereofcan be omitted as appropriate.

In this disclosure, when an element is described as being “on” anotherelement, the element can be directly on the other element, or there canbe one or more elements between the element and the other element.

FIG. 1 is a schematic multilayered structural view illustrating the mainconfiguration of a display device 100 according to an embodiment. Thedisplay device 100 includes a display panel P and an illumination device1. The display panel P is a light transmissive display panel anddisplays images using transmitted light. Although light thatschematically travels along a Z direction is denoted by a referencenumeral L in FIG. 1 , light from the illumination device 1 is notlimited to light along the Z direction.

To be specific, the display panel P is illuminated from one surface(rear surface P1) side and displays images on the other surface (displaysurface P2) side. Although the display panel P is a transmissive liquidcrystal display panel in which a plurality of pixels are arranged, forexample, it may be a transflective liquid crystal display panel or atransmissive display panel using another system. The illumination device1 is provided on the one surface side of the display panel P andilluminates the display panel P. In the following description, threedirections orthogonal to one another are an X direction, a Y direction,and the Z direction. The illumination device 1 and the display panel Pface each other in the Z direction. The display surface of the displaypanel P corresponds to an X-Y plane. The configuration in which thesethree directions are not orthogonal to one another can also be employed.

FIG. 2 is a schematic perspective view illustrating the mainconfiguration of the illumination device 1 when viewed from the othersurface side. FIG. 2 omits illustration related to a specific shape of alight guiding member 20, which will be described later with reference toFIG. 3 and other figures, in order to simply illustrate a positionalrelation of the light guiding member 20 relative to the otherconfigurations such as a light source substrate 10 and light sources 11.FIG. 2 illustrates an optical sheet 30 such that the configuration ofthe optical sheet 30 is partially cut out in order to illustrate apositional relation between the light sources 11 and the light guidingmember 20 when seen from the other surface side more clearly.

As illustrated in FIG. 1 and FIG. 2 , the illumination device 1 includesthe light source substrate 10, the light sources 11, the light guidingmember 20, and the optical sheet 30. The light source substrate 10 is asubstrate on which the light sources 11 are arranged and has wiringcoupled to the light sources 11, and the like.

The light sources 11 are light emitting elements such as LEDs and emitlight in accordance with supply of electric power. Electric power issupplied to the light sources 11 through the wiring of the light sourcesubstrate 10. A drive circuit (not illustrated) of the LEDs are coupledto the light source substrate 10. To be more specific, terminals areformed on the bottom surfaces of the light sources 11 and are coupled tothe wiring of the light source substrate 10. The light sources 11 can beindividually turned on and off under control of the drive circuit.Brightness thereof when they are on can also be individually adjusted.

As illustrated in FIG. 2 , the light sources 11 are arranged in a matrixwith a row-column configuration that extends in the X direction and theY direction along the X-Y plane. FIG. 2 illustrates an example in which5×5 light sources 11 including five light sources 11 aligned in the Xdirection and five light sources 11 aligned in the Y direction, arearranged in a matrix; however, the number and arrangement of lightsources 11 are desirably set. The arrangement of the light sources 11 isnot limited to the above-mentioned matrix form; and various arrangementforms including a zigzag arrangement, a radial arrangement, and anarrangement obtained by omitting a part of any of these arrangementforms can be employed.

As schematically indicated by arrows from the light source 11 in FIG. 1, the light sources 11 emit light radially. To be more specific, lightfrom the light sources 11 is output not only from the upper surfaces ofthe light sources 11 but also from the side surfaces thereof. That is tosay, most of the light beams from the light sources 11 have not only acomponent in the Z direction but also components in the X direction andthe Y direction. Accordingly, light from the light sources 11 includeslight in the direction along the X-Y plane without being limited tolight in the Z direction.

The light guiding member 20 has a plurality of holes (through-holes) 21with predetermined intervals and a light guiding portion D surroundingthe holes 21. The light guiding member 20 is arranged stacking on thelight source substrate 10, so that the light sources 11 are housed inthe holes 21.

Although the light guiding member 20 is made of synthetic resin or glasshaving translucency, the specific material thereof can be changed asappropriate as long as the light guiding member 20 is a translucentmember that reflects or transmits light depending on the angle of asurface thereof with respect to light. That is to say, the refractiveindex, reflectivity, and light diffusibility of the light guiding member20 can be changed as appropriate. The light guiding member 20 guideslight from the light sources 11 to the display panel P side. Specificinfluences on light from the light sources 11 by the light guidingmember 20 will be described later.

The optical sheet 30 diffuses light emitted from the light sources 11.The optical sheet 30 illustrated in FIG. 2 is configured by stackingfour optical sheets 31, 32, 33, and 34 having different opticalcharacteristics but is not limited thereto. The optical sheet 30 may bean optical sheet of a single layer or an optical sheet having amultilayered structure of two layers, three layers, or five or morelayers.

FIG. 3 is an X-Y plan view illustrating a relation between the lightsources 11 and the light guiding member 20. FIG. 4 is a cross-sectionalview cut along line A-A in FIG. 3 . The light guiding member 20 has theholes 21 provided with the predetermined intervals and the light guidingportion D provided so as to surround the holes 21. The light guidingportion D has second inclined surfaces 22, first inclined surfaces 23,and facing surfaces 24. The second inclined surfaces 22 form a part ofthe wall surfaces of the holes 21. The light guiding member 20 is madewith a plate material having translucency, and a plane including thefacing surfaces 24 can be referred to as an output surface and a planeincluding a surface that is in contact with the light source substrate10 can be referred to as a rear surface.

FIG. 5 is an enlarged cross-sectional view illustrating a configurationwithin a portion B in FIG. 4 . The holes 21 penetrate from the surface(rear surface) of the light guiding member 20 on the light sourcesubstrate 10 side to the surface (output surface) thereof on the displaypanel P side. Light emitted from the light sources 11 in the Z directionpasses through the optical sheet 30 and illuminates the display panel P.

To be more specific, the holes 21 have first openings 21 a on the rearsurface side and second openings 21 b on the output surface side, andboth of them have rectangular shapes in the X-Y plane. In theembodiment, the light sources 11 have rectangular shapes in the X-Yplane and have dimensions of 1 [mm] in the X direction and the Ydirection. Dimensions of the first openings 21 a in the X direction andthe Y direction are 1.6 [mm]. Each of the light sources 11 is ideallyarranged at the center of the hole 21 in an X-Y plane viewpoint but isnot necessarily arranged at the center strictly. It is sufficient thatthe light source 11 is arranged in the hole 21. The above-mentionednumerical values are illustrative examples and can be changed asappropriate. The light guiding member 20 thus has a light guidingstructure provided with the holes 21 that open in the first direction (Zdirection) and in which the light sources 11 are arranged.

The second inclined surfaces 22 are provided on the output surface sideof the light guiding member 20. The second inclined surfaces 22 areinclined with respect to the Z direction and the X-Y plane. To bespecific, the second inclined surface 22 is an inner wall surface of thehole 21 extending continuously from an intermediate portion 21 d of thehole 21, which serves as a base end, in the direction away from thecenter line 21 c of the hole as a distance from the output surface isdecreased. The second inclined surface 22 causes a part of light emittedfrom the light source 11 to be output without being influenced by atleast one of reflection and refraction by the light guiding member 20,that is, without passing through the light guiding member 20. Such lightcontains a large component in the Z direction and is output toward thedisplay panel P with sufficient luminance without needing the guidanceby the light guiding member 20. Each of the intermediate portion 21 d asthe base end portion of the second inclined surface 22 is preferablyprovided on the rear surface side with respect to the center of thelight guiding member 20 in the thickness direction. The intermediateportion 21 d is preferably provided on the rear surface side withrespect to the output surface of the light source 11 housed in the hole21, and more preferably provided on the rear surface side with respectto a position corresponding to the half of the height of the lightsource 11 from the light source substrate 10.

The first inclined surfaces 23 are provided on the rear surface side ofthe light guiding member 20. The first inclined surfaces 23 are inclinedwith respect to the Z direction and the X-Y plane. To be specific, thefirst inclined surface 23 extends continuously from an opening edge 25of the first opening 21 a of the hole 21, which serves as a base end, inthe direction away from the center line 21 c of the hole 21 as adistance from the output surface is decreased. Inclination of the firstinclined surface 23 extends continuously from the opening edge 25serving as the base end to a termination end CL farthest from the lightsource 11 in a desired direction along the X-Y plane. The position ofthe termination end CL is located on, for example, an intermediate linebetween two adjacent holes 21. The distances from the center lines 21 cof the two adjacent holes 21 to the intermediate line are equal. A SpaceSP is formed between the two adjacent holes 21. Roof portions of thespace SP are two first inclined surfaces 23 that are symmetricallycontinuous with respect to the above-mentioned intermediate line as theboundaries. As described above, the light guiding member 20 has a lightguiding structure in which the first inclined surfaces 23 inclined withrespect to the Z direction and the X-Y plane are formed.

An arrangement pitch of the light sources 11 in each of the X directionand the Y direction is 6 [mm] in the embodiment. A pitch of the holes 21of the light guiding member 20 is also 6 mm. Thus, a distance from thecenter of a certain hole 21 to the termination end CL in the X direction(Y direction) is 3 [mm]; however, the distance is merely examples andcan be changed as appropriate.

As illustrated in FIG. 5 , the light guiding member 20 has aconfiguration that is symmetric between the two adjacent light sources11 with the termination ends CL interposed therebetween.

As illustrated in FIG. 5 , light L2 and light L3 that have entered theinner circumferential surface of the hole 21 along the X-Y plane, morespecifically, parts of light output from the light source 11 that havelarger X-Y components than a Z-direction component or that containnegative components in the Z direction are refracted and incident fromthe second inclined surface 22 toward the inside of the light guidingmember 20 and then travel to the side of the first inclined surface 23.The light L2 and the light L3 are reflected to the display panel P sideby the first inclined surface 23 and thereby travel to the display panelP side at farther positions from the light source in comparison withoutput angles from the light source 11. The first inclined surface 23and the second inclined surface 22 have different inclination angleswith respect to the X-Y plane. The first inclined surface 23 has a moreacute inclination angle with respect to the X-Y plane than that of thesecond inclined surface 22.

The inclination angle of the first inclination surfaces 23, theinclination angle of the second inclined surfaces 22, and positions oforigin points thereof are desirably adjusted such that light outputalong the X-Y plane in light emitted from the light sources 11 is madeeasier to travel to the display panel P side.

Each of the facing surfaces 24 is provided on the output surface side ofthe light guiding portion D. The facing surface 24 is along the X-Yplane and faces the optical sheet 30. The facing surface 24 is a surfacefrom which light passing through the inside of the light guiding portionD is output, as indicated by the light L2 and the light L3 in FIG. 5 .The output angles of the light L2 and the light L3 are slightlyincreased by refraction occurred in the facing surface 24.

The surfaces of the light sources 11 and the light guiding member 20that face the optical sheet 30 are flush with each other along the X-Yplane in the embodiment. To be specific, a thickness H of the lightguiding member 20 corresponds to the height of the light sources 11 fromthe light source substrate 10, as illustrated in FIG. 5 . In otherwords, the upper surfaces of the light sources 11 and the output surfaceof the light guiding member 20 match with each other. Positions of thefacing surfaces 24 in the Z direction with respect to the light sourcesubstrate 10 are the same as the positions of the upper surfaces of thelight sources 11, and the light source substrate 10 serve as bottomportions of the light sources 11. A configuration in which the uppersurfaces of the light sources 11 and the output surface of the lightguiding member 20 are not flush with each other can also be employed.For example, a configuration in which the upper surfaces of the lightsources 11 are closer to the light source substrate 10 than the outputsurface of the light guiding member 20 is, can also be employed. In thiscase, the upper surfaces (top portions) of the light sources 11 arelocated in the respective holes 21.

Although the thickness H of the light guiding member 20 is 0.8 [mm] inthe embodiment, this is merely an example and can be changed asappropriate.

Hereinabove, according to the embodiment, as in the case of the light L2and the light L3 described with reference to FIG. 5 , light from thelight source 11 can be made to travel to the display panel P side moreefficiently by reflection of the light L2 and the light L3 by the firstinclined surface 23 in the light guiding portion D. When light passesthrough the inside of the light guiding member 20 without being outputdirectly from the vicinity of the light source 11 not through the lightguiding portion like the light L2 and the light L3, the light can bediffused to farther positions from the light source 11 in the X-Y planeviewpoint. Consequently, luminance unevenness in the X-Y plane viewpointthat would be caused depending on the distances from the light sources11 can be reduced.

When the light guiding portion D is not interposed in a light path bypresence of the second inclined surface 22 as in the case of the lightL1 described with reference to FIG. 5 , light traveling toward thedisplay panel P side without reflection can be made to travel toward thedisplay panel P side as it is.

The light guiding portion D is provided so as to surround the lightsources 11. The thickness of the light guiding member 20 is therebyreduced to the thickness H corresponding to the thickness of the lightsources 11. To be more specific, the light guiding portion D is notprovided directly above nor around the light sources 11, and light fromthe light sources 11 that has a larger component in the Z direction thanthe components in the X direction and the Y direction is output to thedisplay panel P side without passing through the light guiding portionD. The thickness H of the light guiding member 20 is therefore reducedto the thickness of the light sources 11, thereby providing a thinnerillumination device 1, eventually a thinner display device 100.

If no light guiding member 20 is provided, as illustrated in FIG. 15 , alarge gap ap (for example, having a size of equal to or greater than theheight of the light sources 11) for light diffusion needs to be providedbetween the light sources 11 and the optical sheet 30 in order todiffuse light from the light sources 11, that is, sufficiently reduceluminance unevenness between the light sources. The gap ap increases thethickness of the entire display device, which makes it more difficult toreduce the thickness thereof. By contrast, according to the embodiment,the gap ap can be reduced (for example, to a gap equal to or smallerthan the height of the light sources 11) in comparison with a case inwhich no light guiding member 20 is provided, as illustrated in FIG. 1 ,thereby providing the thinner display device 100.

Although the gap ap may be 0 or a value larger than 0, it can be set tobe equal to or smaller than 1 [mm] even when the pitch of the lightsources 11 in the embodiment is taken into consideration.

Modifications

Hereinafter, modifications of the embodiment will be described withreference to FIG. 6 to FIG. 11 . In explanation of the modifications,the same reference signs denote similar components to those in theembodiment, and duplicate explanation thereof is omitted.

First Modification

FIG. 6 is an enlarged cross-sectional view illustrating a characteristicconfiguration in a first modification. FIG. 6 and FIG. 7 to FIG. 9 ,which will be described later, are cross-sectional views illustrating aconfiguration within the portion B in FIG. 4 in description of theembodiment in an enlarged manner.

Inclined surfaces provided on the rear surface side of a light guidingmember 20A in the first modification include a plurality of slopes(slopes 23A and grooves 26) that are different in positions with respectto the light sources 11 and different in angles with respect to the X-Yplane. To be specific, the light guiding member 20A in the firstmodification includes the slopes 23A provided instead of the firstinclined surfaces 23 in the embodiment and the grooves 26 provided atintermediate positions between the slopes 23A adjacent to each other inthe arrangement direction of the holes 21. The slope 23A and the groove26 have different inclination angles with respect to the X-Y plane. Inthe example illustrated in FIG. 6 , the groove 26 has a larger anglewith respect to the X-Y plane than that of the slope 23A and is providedbehind facing surface 24A. More light can thereby be output from thefacing surfaces 24A.

Although the slopes 23A illustrated in FIG. 6 and FIG. 7 to FIG. 9 ,which will be described later, have a smaller inclination angle withrespect to the X-Y plane than that of the first inclined surfaces 23,they are merely an example and are not limited thereto. The inclinationangle of the slopes 23A with respect to the X-Y plane may be similar tothat of the first inclined surfaces 23 or may be larger than that of thefirst inclined surfaces 23.

Slopes 22A illustrated in FIG. 6 and FIG. 7 to FIG. 9 , which will bedescribed later, are provided instead of the second inclined surfaces 22in the embodiment. Although the slopes 22A have a smaller inclinationangle with respect to the X-Y plane than that of the second inclinedsurfaces 22, they are merely an example and are not limited thereto. Theinclination angle of the slopes 22A with respect to the X-Y plane may besimilar to that of the second inclined surfaces 22 or may be larger thanthat of the second inclined surfaces 22. With the above-mentionedinclination angle, the facing surfaces 24A, 24B, 24C, and 24Dillustrated in FIG. 6 and FIG. 7 to FIG. 9 , which will be describedlater, have a smaller width in the X direction than that of the facingsurfaces 24; however, they are merely an example and are not limitedthereto. The width of each of the facing surfaces 24A, 24B, 24C, and 24Ddepends on the inclination angle of the slopes 22A with respect to theX-Y plane. The grooves 26 have a larger angle with respect to the X-Yplane than that of the slopes 22A.

Second Modification

FIG. 7 is an enlarged cross-sectional view illustrating a characteristicconfiguration in a second modification. In second and subsequentmodifications, difference from the first modification described withreference to FIG. 6 is explained, the same reference signs denotesimilar components, and duplicate explanation thereof is omitted.

In the second modification and third and fourth modifications, whichwill be described later, the slopes 22A and a plurality of slopes thatare different in positions with respect to the light sources 11 anddifferent in angles with respect to the X-Y plane, are provided on theoutput surface side of a light guiding member. To be specific, a lightguiding member 20B in the second modification has, in addition to theslopes 22A, a groove 27 in a facing surface 24B.

Each of the grooves 27 has inclined surfaces each of which becomescloser to the first inclined surface 23 from the facing surface 24B asit becomes closer to the termination end CL from the side close to thehole 21. The slopes 22A and the grooves 27 thus have differentinclination angles with respect to the X-Y plane.

Third Modification

FIG. 8 is an enlarged cross-sectional view illustrating a characteristicconfiguration in a third modification. A light guiding member 20C in thethird modification has, in addition to the slopes 22A, a plurality ofgrooves 28 in a facing surface 24C. Each groove 28 is shallower than thegroove 27 but may be the same as or deeper than the groove 27. Theconfiguration in which each groove 28 becomes deeper from the outermostside toward the inner side can also be employed.

Fourth Modification

FIG. 9 is an enlarged cross-sectional view illustrating a characteristicconfiguration in a fourth modification. A light guiding member 20D inthe fourth modification has, in addition to the slopes 22A, a pluralityof projecting portions 29 projecting toward the display panel P sidefrom a facing surface 24D.

FIG. 10 is an X-Y plan view illustrating a relation between the lightsources 11 and the light guiding member 20D in the fourth modification.The projecting portions 29 are provided along the Y direction on thefacing surfaces 24D between the light sources 11 aligned in the Xdirection. More than one projecting portion 29 is provided on eachfacing surface 24D. The projecting portions 29 along the Y direction arealigned in the X direction. The projecting portions 29 are providedalong the X direction on the facing surfaces 24D between the lightsources 11 aligned in the X direction. More than one projecting portion29 is provided on each facing surface 24D. The projecting portions 29along the X direction are aligned in the Y direction.

A cross-sectional shape of each projecting portion 29 is an isoscelestriangular shape having an apex on the display panel P side, asillustrated in FIG. 9 . An angle of the inclined surfaces of theprojecting portion 29 with respect to the X-Y direction is larger thanthose of the slopes 22A and 23A. This configuration can increase outputlight from the facing surfaces 24D.

Covering members 40 are provided at positions at which the projectingportions 29 along the X direction and the projecting portions 29 alongthe Y direction intersect with each other. The covering members 40 aremade to adhere to and are fixed to the light guiding member 20D on thedisplay panel P side so as to cover top portions of the projectingportions 29 on the display panel P side. The covering members 40 are,for example, colorless covers made of resin having translucency but arenot limited thereto, and a specific material thereof can be changed asappropriate.

In the fourth modification, the optical sheet 30 is stacked on thedisplay panel P side of the light guiding member 20D on which thecovering members 40 are provided. With this configuration, influences onoptical characteristics of the optical sheet 31 due to physical contactof the projecting portions 29 can be prevented.

The number of grooves 28 illustrated in FIG. 8 and the number ofprojecting portions 29 illustrated in FIG. 9 that are formed between thetwo adjacent light sources 11 are six; however, they are merely anexample and are not limited thereto. The number of grooves 28 and thenumber of projecting portions 29 between the two adjacent light sources11 can be changed as appropriate. The angles, sizes, numbers of thegrooves 28 and projecting portions 29 can be changed as appropriate.

Fifth Modification

FIG. 11 is an X-Y plan view illustrating a relation between the lightsources 11 and a light guiding member 20E in a fifth modification. Thefirst openings 21 a and the second openings 21 b of the holes 21 areformed into circular shapes in this modification. With these shapes, theinclined surfaces are formed into mortar shapes.

FIG. 12 is a diagram illustrating an example of the configuration onwhich mirror finishing has been performed. The mirror finishing for morereliable reflection of light to the display panel P side may beperformed on the first inclined surfaces 23 (or the slopes 23A and thegrooves 26) on the light source substrate 10 side. FIG. 12 illustratesmirror-finished portions 23M that are further provided on the lightsource substrate 10 side of the first inclined surfaces 23 of theconfiguration illustrated in FIG. 5 ; however, the configuration is notlimited thereto, and a configuration similar to the mirror-finishedportions 23M may be provided also on the light source substrate 10 sideof the slopes 23A and the grooves 26. The mirror-finished portions 23Mare provided by forming thin films made of metal, alloy, or compoundsuch as an oxide by working processing such as vapor deposition to causethe thin films to function as mirror surfaces, for example. A specificformation method of the mirror-finished portions 23M is not limitedthereto and can be changed as appropriate. For example, mirror sheetsmay be attached.

FIG. 13 and FIG. 4 are diagrams each of which illustrates an example ofthe configuration of the light guiding member 20 in which the secondinclined surfaces 22 are omitted. The second inclined surfaces 22described with reference to FIG. 5 and other figures are not essential.As illustrated in FIG. 13 , for example, the configuration provided byomitting the second inclined surfaces 22 from the light guiding member20 in FIG. 5 may be employed.

In the example illustrated in FIG. 13 , the positions of the facingsurfaces 24 in the Z direction with respect to the light sourcesubstrate 10 are the same positions as the upper surfaces of the lightsources 11. The light source substrate 10 serve as the bottom portionsof the light sources 11. A configuration in which the upper surfaces ofthe light sources 11 and the output surface of the light guiding member20 are not flush with each other can also be employed. For example, asillustrated in FIG. 14 , a configuration in which the upper surfaces(output surfaces) of the light sources 11 are closer to or farther fromthe light source substrate 10 than the output surface of the lightguiding member 20 is, can also be employed. FIG. 14 illustrates outputsurfaces 11 b as the upper surfaces the light sources 11 at thepositions closer to the light source substrate 10. In this case, theupper surfaces (top portions) of the light sources 11 are located in therespective holes 21. FIG. 14 also illustrates output surfaces 11 a asthe upper surfaces of the light sources 11 at the positions farther fromthe light source substrate 10. In this case, the upper surfaces (topportions) of the light sources 11 are located outside the respectiveholes 21. For example, the illumination device illustrated in FIG. 14 isprovided facing a liquid-crystal optical element PX having a lensfunction of diffusing and concentrating light passing therethrough.Obviously, as in the embodiment and the other modifications, theconfiguration in which the illumination device is provided on the rearsurface side of another liquid-crystal element including the displaypanel P can be employed.

Other operational effects provided by the aspect described in theembodiment that are obvious from description of the presentspecification or at which those skilled in the art can arrive asappropriate should be interpreted to be reasonably provided by thepresent disclosure.

What is claimed is:
 1. A display device comprising: a display panelconfigured to transmit light; and an illumination device provided on arear surface side of the display panel, wherein the illumination deviceincludes a plurality of light sources configured to emit light, and alight guiding member that has translucency and is arranged at the rearsurface side of the display panel, the light guiding member has aplurality of holes each of which passes through the light guiding membercompletely in a first direction that intersects a rear surface of thedisplay panel, each of the light sources is housed in a correspondingone of the holes, a rear surface of the light guiding member has a firstinclined surface inclined upwardly from a light source housed in one ofthe holes, a front surface side of the light guiding member has a secondinclined surface inclined upwardly from the light source housed in theone of the holes, and an angle of the first inclined surface to a centerline of the one of the holes is greater than an angle of the secondinclined surface to the center line, a direction of the center linebeing perpendicular to a main surface of the display panel.
 2. Thedisplay device according to claim 1, wherein the first inclined surfaceincludes a plurality of slopes that are different in angles with respectto the center line.
 3. The display device according to claim 1, whereinthe second inclined surface includes a plurality of slopes that aredifferent in angles with respect to the center line.
 4. The displaydevice according to claim 3, wherein a projecting portion projectingtoward the display panel provided between the second inclined surface atthe front surface side.
 5. The display device according to claim 4,comprising a covering member on the projecting portion.
 6. The displaydevice according to claim 1, wherein the first inclined surface has alower end that is an lowermost end from which the first inclined surfaceextends upward, the second inclined surface extends to the one of theholes at a lower end that is an lowermost end from which the secondinclined surface extends upward, and the lower end of the secondinclined surface is closer to the light source than the lower end of thefirst inclined surface.
 7. The display device according to claim 1, theangle of the first inclined surface to the center line of the one of theholes, the holes each passes through from a bottom of the light guidingmember to a top of the light guiding member in the first direction, isgreater than an angle of the second inclined surface to the center line.8. An illumination device provided on a rear surface side of aliquid-crystal element, the illumination device comprising: a pluralityof light sources; and a light guiding member that has translucency andis arranged between the light sources, wherein the light guiding memberhas a plurality of holes each of which passes through the light guidingmember completely in a first direction that intersects a rear surface ofthe liquid-crystal element, each of the light sources is housed in acorresponding one of the holes, a rear surface of the light guidingmember has a first inclined surface inclined upwardly from a lightsource housed in one of the holes, a front surface side of the lightguiding member has a second inclined surface inclined upwardly from thelight source housed in the one of the holes, and an angle of the firstinclined surface to a center line of the one of the holes is greaterthan an angle of the second inclined surface to the center line, adirection of the center line being perpendicular to a thicknessdirection of the light guiding member.
 9. The illumination deviceaccording to claim 8, wherein the first inclined surface includes aplurality of slopes that are different in angles with respect to thecenter line.
 10. The illumination device according to claim 8, whereinthe second inclined surface includes a plurality of slopes that aredifferent in angles with respect to the center line.
 11. Theillumination device according to claim 10, wherein a projecting portionprojecting toward the liquid-crystal element.
 12. The illuminationdevice according to claim 11, comprising a covering member on theprojecting portion.
 13. The illumination device according to claim 8,wherein the first inclined surface has a lower end that is an lowermostend from which the first inclined surface extends upward, the secondinclined surface extends to the one of the holes at a lower end that isan lowermost end from which the second inclined surface extends upward,and the lower end of the second inclined surface is closer to the lightsource than the lower end of the first inclined surface.
 14. The displaydevice according to claim 8, the angle of the first inclined surface tothe center line of the one of the holes, the holes each passes throughfrom a bottom of the light guiding member to a top of the light guidingmember in the first direction, is greater than an angle of the secondinclined surface to the center line.
 15. A light guiding member havingtranslucency comprising: a hole passing through the light guiding membercompletely in a first direction that intersects a rear surface of thelight guiding member, so as to house a light source; a rear surfacehaving a first inclined surface inclined upwardly from a center line ofthe hole, a direction of the center line being perpendicular to athickness direction of the light guiding member; and a front surfacehaving a second inclined surface inclined upwardly from the center lineof the hole, wherein an angle of the first inclined surface to a centerline of the hole is greater than an angle of the second inclined surfaceto the center line.
 16. The light guiding member according to claim 15,wherein the first inclined surface includes a plurality of slopes thatare different in angles with respect to the center line.
 17. The lightguiding member according to claim 15, wherein the second inclinedsurface includes a plurality of slopes that are different in angles withrespect to the center line.
 18. The light guiding member according toclaim 15, wherein a projecting portion projecting upwardly from thefront surface.
 19. The light guiding member according to claim 18,comprising a covering member on the projecting portion.
 20. The lightguiding member according to claim 15, wherein the first inclined surfacehas a lower end that is an lowermost end from which the first inclinedsurface extends upward, the second inclined surface extends to the oneof the holes at a lower end that is an lowermost end from which thesecond inclined surface extends upward, and the lower end of the secondinclined surface is closer to the light source than an lower end of thefirst inclined surface.
 21. The display device according to claim 15,the angle of the first inclined surface to the center line of the one ofthe holes, the holes each passes through from a bottom of the lightguiding member to a top of the light guiding member in the firstdirection, is greater than an angle of the second inclined surface tothe center line.